Spark plug



Aug. 25, 1925. 1,550,897

J. FONELLI SPARK PLUG Filed July 1924 INVENTOR &4 M

" ORNEY UNITED STATES PATENT OFFICE.

JOHN FONELLI, OF NEW YORK, N. Y.

i SPARK PLUG.

Application filed. July 3, 1924. Serial No. 723,887.

To all 20 [mm it may concern Be it known that I, JOHN FoNELLI, a citizen of Italy, residing at New York city, borough of Manhattan, in the county of New York and State of New York, have invented certain new and useful Improvements in Spark Plugs, of which the following is a specification.

This invention relates to spark plugs and more particularly to spark plugs which are rendered self cleansing through the proper utilization of exploding cylinder gases.

Among the objects of this invention is to provide a simple and commercially practical spark plug which will so utilize the exploding cylinder gases as to direct the same upon all parts of the electrodes whereby the high velocities of such gases will be of direct benefit in serving to keep the electrodes purged from carbon, oil, and the like.

Another object of this invention is to provide an arrangement for a self-cleansing spark plug whereby direct and instantaneous access of the cylinder gases is available about the electrodes, to insure not only positive and uniform action of the spark plug, but the most thorough possible cleansing of the electrodes when said gases explode.

Vith the foregoing and other objects in view the invention consists in the arrangement and combination of parts hereinafter described and claimed, and while the invention is not restricted to the exact details of construction disclosed or suggested herein, still for the purpose of illustrating a practical embodiment thereof reference is had to the accompanying drawings, in which like reference characters designate the same parts in the several views, and in which Figure 1 is a sectional elevation of the spark plug.

Fig. 2 is a plan view.

Fig. 3 is a bottom plan.

Fig. 4 is a transverse section on the line 44 of Fig. 1.

Referring now more specifically to the drawings, 10 is a plug body having a bottom 11 shown as integral therewith. The body or shell has a hexagonal head 12 and is provided with an internal shoulder 13 facing the outer end. A male thread i l-adjoining the bottom 11 provides for the rigld insertion of the plug into the engine body, while a female thread 15 is adapted to r'eceive the hexagonal nut 16. A core 17 consists of porcelain or other insulating material having a central peripheral enlargement 18, and an axial hole 19 co-extensive in length with the core and having an enlarged concentric opening of preferably cylindrical shape adjacent the inner end of the plug. Gaskets 21 and 21 of suitable nature are adapted to pack the joints between the enlargement and the surrounding parts, the former with the nut 16 and the latter with the shoulder 13 of the plug body.

The inner end of the shell is essentially closed, as distinguished from the usual open structure, but the bottom 11 is provided with a central hole 22 shown as substantially rectangular. In the formation of this hole a tongue 23 is formed as by stamping or punching outward from the body a. portion of the disk or bottom 11. This tongue is shown formed at a shorter side of the rectangle and is reduced to a triangular form the the like, the vertex or point of the triangle being at the free end of the tongue. This tongue is bent outwardly of the plug and substantially at right angles to the bottom 11, the point or vertex or the tongue, which constitutes an electrode being bent in opposite direction to the bend aforesaid so that said electrode will extend across the opening 22 and be substantially parallel to and spaced below the bottom 11. A hole or perforation 2 1 is formed in the electrode 23, offset slightly from the axis of the plug body, the axis of said hole being substantially parallel to the axis aforesaid. Drilled or otherwise formed in the walls of the plug body are four or other suitable number of radial holes 25, immediately adjacent to the bottom .11, the combined area of which is approximately equal to the area of the opening 22.

A conductor element 26 has a stop shoulder 27 spaced therealong and an integral axial extension 28 of reduced diameter forming an electrode, the end whereof is maintained in spaced relation to its co-acting electrode 23 by means of the stop shoulder 27 and the predetermined sizes and proportions of the cooperating core and plug body. The axis of the conductor element, and consequently also that of the electrode 28, coincides with the axis of the core and plug body. The, end of the conductor element remote from the electrode is screw threaded as at 29 so as to receive the usual conductor wire binding means.

The construction of the spark plug will be seen to be at once simple and reliable. It consists of but three main or essential parts, these being the plug body, the internal core, and the conductor element. The plug lends itself therefore readily to the large scale standardized production 1nethods of manufacturing.

It is, moreover, certain and reliable in operation. For assuming the cylinder to be full of a proper explosive mixture, as soon as the spark jumps the gap between the electrodes, the gaseous mixture suffers an instantaneous and tremendous increase in temperature and pressure, combustion proceeding with the usual violence and rapidity, and accompanied as a consequence by the usual eddying of the burning gases, which continues after combustion has been completed and the burnt gases are being drawn off through the exhaust. In my invention I have utilized the force of these gases to blow or otherwise sweep any accumulations of carbon, oil, and the like which normally deposit on the electrodes in an engine cyl' inder, while still maintaining the simplicity of the spark plug. While the opening 22 insures a suflicient volume of gaseous flow about the electrodes, the perforation 2st which is offset from the electrode 28 so as to be directly in the streamline permits part of the gases to pass therethrough, insuring the proper circulation of the gases upon all sides of the tip of the electrode 28. The holes 25, moreover, provide for the free flow and circulation of the gaseous mixture into the chamber 30 whence such mixture when ignited insures complete purging of the contact points while sweeping outward through the opening 22, so that full advantage may be taken of differences in pressure between the regions at the sides and the bottom of the spark plug.

I claim:

1. In a spark plug, the combination with a hollow substantially cylindrical plug body having a bottom and an electrode mounted therein, of another co-operating electrode formed of a substantially fiat tongue struck from said bottom forming thereby an opening in the bottom, said tongue being disposed in substantially parallel relation to the bottom, said body having a circulation hole formed therein for the interior thereof, the axis whereof is spaced from the plane of the tongue.

2. In a spark plug, the combination with a plug body having a bottom and an electrode mounted therein, of another co-acting electrode formed of a substantially fiat tongue struck from said bottom and disposed in substantially parallel relation thereto, said tongue being perforated to permit the passage of gas therethrough for the removal of deposit, said perforation be ing offset from the axis of the first mentioned electrode.

3. In a spark plug, the combination of a plug body having a bottom with a hole therein, said body having a radial hole in the side thereof adjacent to said bottom, and a plurality of electrodes one of which is mounted externally upon said bottom in spaced relation thereto and oppositely disposed to the hole therein, the other electrode projecting into said hole, said hole co-operating with the radial hole aforesaid to permit circulation of gases about the electrodes, said electrodes being arranged so as to fully utilize the purging effect of said gases.

4. The combination as in claim 3 wherein the first mentioned electrode consists of a flat tongue having a perforation therethrough which is offset relatively to the other electrode.

5. The combination as in claim 3 wherein the first mentioned electrode consists of a Hat tongue struck from said bottom while forming said hole, said tongue having a perforation therethrough which is offset relatively to the other electrode.

6. A spark plug comprising a hollow metallic shell having an inner end closure and forming a chamber, said closure having a hole therethrough, a center electrode ex tending through said chamber and through said hole, and a second electrode carried by said closure and extending parallel thereto on the side remote from the chamber.

7. A spark plug as set forth in claim 6 in which the second electrode has a perforation therethrough offset from the axis of the first electrode.

In testimony whereof I affix my signature.

JOHN FONELLI. 

